In Situ Characterization and Interfacial Viscoelastic Properties of Pickering Emulsions Stabilized by AIE-Active Modified Alginate and Chitosan Complexes

Abstract

Pickering emulsions stabilized by polysaccharide–polysaccharide complexes are attractive in many applications. However, how interface films formed by soft particles affect the stability of Pickering emulsions has not been well explored. Herein, we designed aggregation-induced emission (AIE)-active modified alginate (Alg-AIE)/chitosan (CS) polyelectrolyte complex (Alg-AIE/CS complex) colloidal particles that are used to stabilize Pickering emulsions. To explore the relationship between the interface film structure and emulsification properties, the microstructure of emulsions was directly visualized by a combination of confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The wetting properties of Alg-AIE/CS complexes were regulated by changing the amount of CS, which further regulated the aggregation behavior of the interface. The interfacial adsorption behavior of the particles and the physical stability of the emulsions were determined by combining stability analysis and employing a quartz crystal microbalance with dissipation monitoring (QCM-D). The results showed that the addition of CS resulted in more Alg-AIE/CS complexes that could be adsorbed at the oil–water interface, forming thicker and stronger viscoelastic interface films, which improved the stability of the emulsion. Most importantly, in situ visualization technology provided a new way to understand the interfacial properties of Pickering emulsions.

Covalent Bond Interfacial Recognition of Polysaccharides/Silica Reinforced High Internal Phase Pickering Emulsions for 3D Printing

“…Compared with the incomplete interfacial film of 0.591 μm in the emulsion stabilized with Ugi-OA alone, a tighter droplet-particle network structure also formed in the continuous phase, making oil droplets more or less captured and fixed . The thickness and stiffness of the interface film could be effectively controlled, which was beneficial to the designability of the HIPPEs …”

“…Under the coassembly behavior mediated by Schiff base interaction, the droplets will also form a closer bridge and network structure between the droplets, which is more conducive to the long-term stability of HIPPEs. 57 The interfacial film of particle complexes was further studied by CLSM. As shown in Figure 6, only a thin red ring film fluorescently labeled with rhodamine dye was observed around the oil droplets for the emulsion stabilized with Ugi-OA alone, while a complete and clear particle interface film was formed around the droplet costabilized by NPSs.…”

“…58 The thickness and stiffness of the interface film could be effectively controlled, which was beneficial to the designability of the HIPPEs. 57 The QCM-D was used to monitor the interaction strength based on the change in resonance frequency (Δf) and energy dissipation (ΔD) caused by the interaction of the Ugi-OA solution with the quartz chips coated with SNs (silica nanoparticles), ASNs. According to the Sauebrey model (the relationship between the oscillation frequency of the oscillating quartz crystal and the mass change), the adsorption quality of the oil−water interface, the thickness and the structural characteristics of the adsorbed layer were analyzed.…”

Soy Protein Isolate/Genipin-Based Nanoparticles for the Stabilization of Pickering Emulsion to Design Self-Healing Guar Gum-Based Hydrogels

“…According to the stabilization mechanism of Pickering emulsion, the solid particles adsorbed at the interface of water and oil irreversibly, which could prevent the aggregation and Ostwald ripening of the droplets. 36 Compared with emulsions stabilized by small-molecule surfactants, SPI-stabilized emulsions own good interfacial and emulsions activities, for which soybean protein was considered to be an effective emulsifier. However, the native SPI showed a highly folded structure with a rough surface under SEM (Figure 1a), which was probably caused by the aggregated particles.…”

Highly Sensitive Immunochromatographic Detection of Zearalenone Based on Ultrabright Red-Emitted Aggregation-Induced Luminescence Nanoprobes

“…Compared with traditional organic fluorescent dyes, AIEgens with unique optical properties of large Stokes shift, , strong photobleaching resistance, robust photostability, and low random blinking are more suitable for designing and fabricating the high-performance luminescent labels. In the past few years, various AIEgens embedded nanospheres (AIENPs) with excellent luminescence characteristics have been synthesized via different strategies, including swelling, micro-emulsion, and precipitation polymerization methods . With these AIENPs as signal-amplification labels, several AIENP-based LFIAs have been developed to detect different analytes, including mycotoxins, antibiotics, foodborne pathogens, and biomarkers .…”